Delirium Recognition and Diagnosis: EMS has a Role to Play

by Cecilio Padron, MD and DavidArbona, MD FAAEM



EMS is dispatched to a nearby home for a 71-year-old female with confusion.   The patient\’s daughter reports that she has a history of hypertension, hypothyroidism and back pain.  She is currently undergoing evaluation by neurology for dementia as she has been more forgetful over the past year. Her daughter reports that she has been intermittently “off” for the last few days, has been taking medications and eating irregularly.   This morning, she tried to take her to see her primary care doctor, but the patient refused to get into the car.  After discussion with the primary care doctor, her daughter called 911 for assistance.  The patient is oriented x 3 and has a GCS of 15.

Delirium and Why it Matters

Delirium is an acute disorder of attention and cognition that includes the following elements: “alteration of consciousness, change in cognition, acute onset, fluctuating course and reduced attention.” [1] Delirium has three forms: hyperactive, which is characterized by agitation and emotional lability, hypoactive which can be characterized as lethargy, or mixed which has features of both. [2]

Delirium is often confused with dementia, which describes the chronic, progressive impairment that occurs over months to years.  While patients with dementia are at higher risk for delirium, it is important to distinguish the two disorders as delirium represents an acute change with a differential diagnosis prompting evaluation for an underlying acute medical illness(es), decompensated co-morbidities or medication side-effect or interaction.  Delirium is not only associated with increased hospital lengths of stay and health care costs, but increased morbidity and mortality. 

TABLE 1: Comparison of Delirium and Dementia.  Source: ACEP Geriatric Emergency Department Guidelines [10]

TABLE 1: Comparison of Delirium and Dementia. Source: ACEP Geriatric Emergency Department Guidelines [10]

An Often Missed Diagnosis….

Most recent data suggest that approximately 25% of hospitalized patients over the age of 65 have delirium upon the time of admission to the hospital. [3] Up to 40% of patients presenting from nursing homes to the emergency department may have underlying delirium. [3] One prospective study found that ED physicians missed approximately 76% of delirium cases, and these cases were nearly all missed by the hospital physician at the time of admission. [4] To complicate matters further, there is data to suggest that approximately 25% of patients presenting to the ED with delirium will be discharged home [6].  Delirium in ED patients has been associated with increased morbidity and mortality as well as an independent predictor of long-term cognitive decline and dementia. [5,6]

Reasons for the missed diagnosis of delirium are multifactorial.  First, delirium has a fluctuating course and so suspicion may not be present unless a thorough patient history is taken.  In addition, hypoactive delirium may have a more subtle presentation that does not prompt the clinician to consider delirium in the differential diagnosis. While formal cognitive assessment is a quality indicator in the emergency department care of the elderly [7],  ED physicians often work under considerable time and staffing constraints, and these assessments are rarely done.

As life expectancy continues to increase, and EMS systems have become the safety net for communities and public health. This creates an excellent opportunity to significantly improve the geriatric population\’s mortality and quality of life in each agency\’s respective communities. To date, no identifiable studies on the evaluation or screening of patients with delirium in the prehospital setting have been published. Evaluation of a patient\’s cognitive function is largely restricted to orientation status and a GCS score. Although these tools are helpful, they are inadequate for screening for delirium. Delirium classically has a waxing and waning course, making orientation status highly unreliable during a single point in time. The Glasgow Coma Scale was first described in an article published by The Lancet in 1974 by Graham Teasdale and Bryan Jennett. It was intended to be used as an intercommunication tool on the level of consciousness for patients suffering from acute brain injury secondary to trauma and other etiologies of acute neurologic insult. In 1980, the GCS was adopted as part of the standardized assessment in all trauma patients in the Advanced Trauma and Life Support 1st edition. [8] Although essential for evaluating acute traumatic neurologic pathologies, its ease of use and speed of completion has allowed the GCS to suffer from indication creep. As a result, it has been inappropriately used to describe patients\’ mental capacity with chronic neurologic disabilities, such as dementia. Also, it creates false reassurances on patients that may have underlying delirium.


Could EMS be part of the solution?

Figure 2: Delirium Screening Tools. Source: ACEP Geriatric Emergency Department Guidelines [10]

Figure 2: Delirium Screening Tools. Source: ACEP Geriatric Emergency Department Guidelines [10]

History from caregivers and family is often the most vital piece of information to make the diagnosis of delirium, placing frontline EMS personnel in the most advantageous position to screen for the diagnosis [9]. The combination of exposure to a patient\’s home environment, primary interaction with caregivers and family, and constant observation of a patient during on-scene stabilization and transport places frontline EMS personnel in the most advantageous position in healthcare to make the diagnosis of delirium.

Enter the Delirium Triage Screen (DTS) and the Brief Confusion Assessment Method (bCAM). The Geriatric Emergency Department Taskforce\’s most recent guidelines recommend combining the DTS and bCAM to evaluate for delirium in at-risk patients (8). The DTS and bCAM were compared in a prospective observational study to a comprehensive psychiatry exam utilizing the DSM IV criteria. The study found the DTS to have a sensitivity of 98% and the bCAM to have a specificity of 95.8% (9). 

The first step in the DTS/bCAM eval is the delirium triage screen composed of the Richmond Agitation Sedation Scale (RASS) and a single question to screen for delirium. As delirium is a clinical syndrome, the DTS successfully assesses attention deficits and screens for both hyperactive and hypoactive delirium, the latter of which is both most common and most highly missed [4]. If a patient passes the DTS, then there is no need to continue to the bCAM as they have screened out for delirium. If a patient screens positive, however, the next step would be to continue to the bCAM. The first step of the bCAM is to assess the change in baseline mental status and progression of symptoms. These features are best established by EMS that are able to speak with family at home or nursing personnel at nursing facilities. The second step of the bCAM again retests for inattention and cognitive function with a simple question asking the patient to recite the months of the year backward. During the original study, if the patient took longer than 15 seconds to answer the sequential months, then it was considered an error, thus maintaining the brevity of the test [11]. Steps 3 and 4 are reevaluating the RASS and asking a series of questions and commands that evaluate disorganized thinking. A patient is considered bCAM positive if they have feature 1 + feature 2 + (feature 3 or feature 4).

The DTS/bCAM can be completed in less than one minute, especially with the assistance of policy books or apps with accompanying images of the RASS and DTS/bCAM. [11] However, it is imperative to understand the limitations of DTS/bCAM. First, this method has not been validated in the prehospital setting. Furthermore, there is no readily available data on paramedic evaluation of delirium patients at this time. The Han study had a physician and a research assistant evaluating with little variability in sensitivity and specificities between the two. Also, the study excluded anyone younger than 65 years of age, non-verbal patients, non-English speaking, deaf, blind, or comatose, indicating that a patient must be older than 65 and able to communicate to undergo screening. Ultimately, the purpose of DTS/bCAM is to catch the subtler patient presentations of delirium, and, other than age, these exclusion criteria in and of themselves would raise clinical suspicion for delirium.

Case Conclusion

With EMS, the patient was convinced to go to the hospital.  Delirium rather than dementia progression was suspected based on the fluctuating course of symptoms described by the daughter.  Suspected delirium was conveyed via handoff at the hospital, with relay of the description of the waxing and waning course.  Review of the patient’s medication history with daughter revealed that she had recently been started on cyclobenzaprine for back pain, which likely precipitated delirium secondary to the anticholingeric effects.  She was also found to be dehydrated with some acute kidney injury as she had taken less oral intake during her period of mental status change.  She was admitted overnight for IV hydration, with holding of the cyclobenzaprine and frequent re-orienting measures.  Medications were reconciled with the primary care physician and she was discharged back to home the following day in improved condition.


Take home

Delirium is an acute medical condition which presents with fluctuating symptoms of inattention, cognition or level of consciousness.  It often has multifactorial causes, including acute medical conditions and medication effects.  EMS clinicians are well positioned to improve the care of these highly vulnerable patients, by suspecting the diagnosis, taking a thorough patient history and performing delirium assessment . Further research into the evaluation of delirium in the prehospital setting is needed as incidence of these cases will only  increase as the population ages.


EMS MEd Editor, Maia Dorsett MD PhD FAEMS FACEP



1.     Fick, D. M., Agostini, J. V., & Inouye, S. K. (2002). Delirium superimposed on dementia: a systematic review. Journal of the American Geriatrics Society50(10), 1723-1732.

2.     Thom, R. P., Levy-Carrick, N. C., Bui, M., & Silbersweig, D. (2019). Delirium. American Journal of Psychiatry176(10), 785-793.

3.     Inouye SK, Westendorp RG, Saczynski JS: Delirium in elderly people. Lancet 383: 911, 2014. [PMID: 23992774]

4.     Han JH, Zimmerman EE, Cutler N, et al: Delirium in older emergency department patients: recognition, risk factors, and psychomotor subtypes. Acad Emerg Med 16: 193, 2009. [PMID: 19154565]

5.     Han J.H., Eden S., Shintani A., et. al.: Delirium in older emergency department patients is an independent predictor of hospital length of stay. Acad Emerg Med 2011; 18: pp. 451-457.

6.     Witlox, J., Eurelings, L.S.M., de Jonghe, J.F.M., Kalisvaart, K.J., Eikelenboom, P., & van Gool, W.A. (2010, July 28). Delirium in Elderly Patients and the Risk of Postdischarge Mortality, Institutionalization, and Dementia: A Meta-analysis. JAMA304(4), 443-451.

7.     Terrell KM, Hustey FM, Hwang U, et al: Quality indicators for geriatric emergency care. Acad Emerg Med 16: 441, 2009. [PMID: 19344452]

8.     Teasdale, G., Maas, A., Lecky, F., Manley, G., Stocchetti, N., & Murray, G. (2014, August). The Glasgow Coma Scale at 40 years: Standing the test of time. The Lancet Neurology13(8), 844-854.

9.     Mutter, M., & Huff, J. (2020). Altered Mental Status and Coma. J. E. Tintinalli, O. J. Ma, D. M. Yealy, G. D. Meckler, J. S. Stapczynski, D. Cline, et al. , Tintinalli\’s emergency medicine: A comprehensive study guide (pp. 1137-1142). New York, NY: McGraw Hill Education.


11.  Han, J.H., Wilson, A., Vasilevskis, E.E., Shintani, A., Schnelle, J.F., Dittus, R.S., Graves, A.J., Storrow, A.B., Shuster, J., & Ely, E.W. (2013, November). Diagnosing Delirium in Older Emergency Department Patients: Validity and Reliability of the Delirium Triage Screen and the Brief Confusion Assessment Method. Annals of emergency medicine62(5), 457-465.


Disclaimer: This article was supported (in whole or in part) by HCA Healthcare and/or an HCA Healthcare affiliated entity. The views expressed in this publication represent those of the author(s) and do not necessarily represent the official views of HCA Healthcare or any of it’s affiliated entities.


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